Art of working glass.



ivo. 735.796.

UNITED STATES. j

atented August 11, 19033.

OTIS A. MYGATT, OF NEW YORK, N. Y.

ART OF WORKING GL-.ASS.

sPEcIFIcATIoN forming perf; of Lettere recentste. 735,796, dated Auguetil, 1903.

Appneenen tied neeeniberaleoz. Seriana. 133.553. (Nespeeimene.) l

-To all whom t may concern:

Be it known vthat l, OTIs A. MYGATT, a citizen of the United Statesfresiding at New York, in the county of NewYork and State of New York, have invented certain new and useful Improvements in the Art ofl Vorking Glass, of which the following is a specification.

This invention relates to an improvement `in the art of working glass, and is especially heretofore known to me in `my practice as aj manufacturer.

Prism glass globes :have been made in molds heretofore ofthe general character illustrated in Figure 5, in which there is a mold or female die corresponding with the outer surface of the completed article and a plunger corresponding with the inside of such article. A quantity of so-called molten glass is vplaced in the die and the plunger forced down thereon; Nowm'olten glass at any temperature at which it can be molded is not 4av'liquidbut is a more or less plastic or waxy composition. A' quantity of such glass placed in the bottom ofa mold is by pressure of the 'plunger forced upward around-the plunger and between said plunger and the sides of the mold. As the pressuredrives the glass upward in the mold the resistance ofthe rtenacious glass is considerable. The glass does not often flow evenly. It loses its plasticity as it'rises in the mold. lt radiates heat unevenly, and when it sets the texture of different parts of the same article is uneven. Articles pressed in this way must be annealed fora longtime, and there is much loss by defective construction. Where the glass has to be driven into grooves in the mold to form prisms intended to be of precise construction, the difficulty of Ido not herein claim any specific mechanism,

nor do I limit myself to mechanism.

Fig. lis a sectional view of a rolling-bed and roller. Fig. 2 is a plan of the rolling-bed. Fig. 3 isa section of a mold for molding in position over the mold and a dome snrmounting the same, said dome provided with means for applying air or steam pressure to the sheet ofglass. Fig. 4 is a section of a mold with t-he plate blown down to approximately to general form of the mold. Fig. 5 is a section of a mold, showing a pressed semispherical globe. therein and showing a plunger as just withdrawn from the molded article.

Let 1 designate a rolling-bed with a recess 2 in its face. Forja semispherical globe and many other forms of molded articles therecess 2 will be circular and of such depth that a sheet of glass which just fills the recess furnishes just enough glass to make a semispherical globe. A quantity of molten or plastic glass, determined by weight or otherwise to be sufficient to make the desired article, is placed inY the recess 2 and rolled down by roller 3 to the size'and thickness desired. This produces a round plate 4. The plate of vhot 'glass 4 is removed lfrom the recess'2 and instantly placed over the mouth of mold 5. By its own weight the plastic ribbed or prism glass, showing a sheet of glass sheet will sag more or less into the mold and assume the form of a semisphere orbowl in the mold. To insure evenaction,y however, I prefer to place a dome or .cover Gover the plate. The outer rim of this dome rests on and clamps the edge Vof plate 4 around the margin of bowl 8 in the mold. Air, steam, or gas pressure is applied to the plate 4, such being forced into the dome through tube 9 in any suitable way. This has the eect to force the plate 4 into the form of a bowl 44,

rapproximately tting the inside of the mold.

Air-ducts may be provided in the body of the mold (see 7) to permit the escape of air from around the article blown into the mold. The dome 6 is quickly withdrawn, and the plunger l1 is forced down upon the partlyformed article. The pressure of the plunger forces the glass into the mold, and as no part of the plastic glass has far to iiow to reach the grooves or depressions in the mold and plunger a sharper definition can be had than has been common in molded articles heretofore. Much less material is required to insure a complete and well-defined article than where the formation depended on the plunger alone. A glass article produced by this method is likely to be much more uniform in texture and homogeneous in structure than where the plunger has had to force the material a greater distance. As soon as the article has sueiently cooled the plunger is withdrawn and the mold opened to release the article, after which other articles may be molded in like manner.

The rim l2, Fig. 4, should be as narrow as circumstances will warrant. The action of the plunger will draw this more or less into the mold. Any residue may form a rim about the completed article 55 or may be cut away by the action of the plunger or subsequently removed by suitable means.

As the successive steps of my method aregenerally pursued while the glass is hot and before it cools suiciently to lose its plasticity, it is desirable that the rolling-table and the mold be near each other and that the rolled plate be quickly transferred to Ithe mold and there blown and pressed. The rolled plate is not necessarily of uniform thickness. The rolling table may be so formed as to aggregate a quantity of glass at any point where it will be most needed in the further prosecution of the work.

Prismatic glass to be of much use requires to have its surfaces formed with the greatest accuracy. For the transmission of lightit is desirable that the body of the article, such as a lamp globe or shade, be as thin as possible between the prisms, which may be formed on its inner and outer surfaces. By my method I am able to reduce the quantity of material necessary to construct satisfactory shades more perfect in form and much thinner and lighter than such articles have heretofore been made. The illustrations are not. intended to show the form of the prisms on the glass, as such vary to an almost unlimited extent.

Glass articles have been heretofore made which were pressed to approximate form and there blown out into the mold. As the final pressure is a mere air-pressure, no well-deined designs, such as prisms, can be produced by such means. Prism glass has been produced by rolling to approximate form and then impressing prisms on the surface by rolling or by the action of a plunger. means fail to produce as transparent a glass as is desirable.

My method in its entirety contemplates the rolling, then the blowing, then the pressing; but as I believe there is novelty and utility in some of the various steps I desire to claim the method as a whole and also the separate novel steps.

What I claim isl. The method of forming hollow articles of glass, which consists in rolling out a sheet of plastic glass, blowing this into a mold to approximately fit the mold, and immediately compressing in the mold by mechanical action other than blowing.

2. The method of forming articles of glass, which consists in providingaquantity of hot plastic glass closely calculated to form the article, rolling the same to a plate ot' the approximate diameter of the completed article, placing this plate over the mold and confining the edge, blowing the plate into the mold to approximately follow the outline thereof,

then pressing the material into the mold byl mechanical action other than blowing.

3. The method of forming a glass article, which consists in securing the edge of a sheet of hot plastic glass about the edge of a mold, blowing the sheet to the approximate form of the mold by means of air or steam applied to the surface opposite the mold, and completing the formation by the action of a plunger compressing the material into the mold.

4. The method of forming a globe or shade of prismatic glass, which consists in rolling a quantity of hot plastic glass to the general diameter of the globe, forcing it to concavoconvex form in a mold byablowing pressure applied to one side of the rolled material, then quickly pressing to accurate form by the action of a plunger in the mold.

5. The method of making hollow articles of glass, which consists in heating glass to a plastic condition, forming a sheet therefrom, blowing in a mold to the approximate shape of the desired article, then compressing rigidly in the mold by mechanical action.

6. The method of making hollow articles of glass, which consists in heating glass to a plastic condition, forming a sheet therefrom, applying the sheet to a mold and partially shaping' the sheet to the mold by yielding pressure, then pressing the article by rigid mechanical means.

In testimony whereof I afx my signature in presence of two witnesses.

OTIS A. MYGATT.

Witnesses:

IRA FERGUSON, H. E. NAsoN.

Such 

